There are many non-destructive testing and/or XRF analysis applications involving complex situations which require thickness measurement, corrosion inspection and chemical composition analysis on high temperature test objects. As an example, sulfide corrosion of oil pipes is a significant cause of leaks and issues for the refining industry that cause early replacements, unplanned outages, loss of property, and, in extreme cases, injury to workers. According to the American Petroleum Institute (API) Recommended Practice 939-C (Guidelines for Avoiding Sulfidation Corrosion Failures in Oil Refineries), ⅓ of all high temperature sulfidic corrosion failures are due to low silicon content in the piping. The inspection of a pipe's corrosion status, chemical composition would require conducting XRF analysis on high temperature pipes.
Elemental analysis of oil refinery pipes with handheld, self-contained X-Ray Fluorescence (XRF) devices is a preferred method to help predict and prevent pipe failures from occurring. These handheld devices typically have a front plate window whereby an X-ray is emitted out to a test object, and the responding energy returning from the test object enters back to a detector in the device. On regular test objects of which high temperature is not present, the devices are usually held by operators in such a way that the front plate touches the surface of the test object.
However when the test object is of high temperature during an XRF operation, existing XRF device designs present problems as to how the operator can hold the handheld so that the front plate window can be placed in relation to the test object in the desirable manner. First, if the front-plate window touches the surface of the test object being tested, the front plate window might sustain damage or too much heat is trapped between the front plate and the test object. And high temperature oil pipes might contaminate the window, invalidating the result. Therefore some gap between the front plate window and the testing surface is desirable. Second, if the gap between the front-plate and the sample is too great, not enough X-ray energized energy from the sample is captured during the test for the analyzer, and the result is too faint to be accurate. Lastly, if the gap between the front-plate window and the sample being tested wobbles and is inconsistent, the air from the varying gaps attenuates the X-Rays inconsistently (more so for lighter elements such as silicon), and distorts the test results of the sample.
U.S. Pat. No. 7,939,450 B2 discloses an apparatus and method for processing a substrate with silicon to control spaces between the layers, and eliminate damage to transistor structures. While this method optimally automates the placement of layer spacing (and prevents the transfer of heat from the material), the solution does not solve the risk of potential damage to a front plate window.
U.S. Pat. No. 2012/0294418 A1 discloses a method of using a goniometer in order to rotate a testing sample to a precise angular position for XRF analysis. This solution though does not minimize the risk of contamination of the front-plate, nor does it allow an air flow that creates a gap which prevents heat from being transferred from the sample to the XRF analyzer.
U.S. Pat No. 2014/0204377 A1 discloses an auto-calibration, auto-clean, and auto-focus functionality for spectroscopic instruments (including XRF test devices) from a controller that configures motors to move an optics stage and a laser, in order to protect a front plate window. However, this solution is heavily dependent on software operation, and does not have the practicality of a simpler mechanical solution.
An inexpensive, easy to set up solution that can save the display window of an XRF device from abrasion and contamination, yet maintain a close and steady distance from a sample being tested, would be of great economic and ergonomic value. It would speed up XRF testing, reduce equipment replacement on a portable XRF testing device, and retain a higher percentage of valid test samples.